From d0b608af3178bc674936f4b1c6cce00591ebbf09 Mon Sep 17 00:00:00 2001 From: Andrii Kushch Date: Tue, 8 Mar 2022 20:18:32 +0100 Subject: tracing: New OpenTelemetry module (#4361) * opentelemetry: create a new module * fix imports * fix test * Update modules/caddyhttp/opentelemetry/README.md Co-authored-by: Dave Henderson * Update modules/caddyhttp/opentelemetry/README.md Co-authored-by: Dave Henderson * Update modules/caddyhttp/opentelemetry/README.md Co-authored-by: Dave Henderson * Update modules/caddyhttp/opentelemetry/tracer.go Co-authored-by: Dave Henderson * rename error ErrUnsupportedTracesProtocol * replace spaces with tabs in the test data * Update modules/caddyhttp/opentelemetry/README.md Co-authored-by: Francis Lavoie * Update modules/caddyhttp/opentelemetry/README.md Co-authored-by: Francis Lavoie * replace spaces with tabs in the README.md * use default values for a propagation and exporter protocol * set http attributes with helper * simplify code * Cleanup modules/caddyhttp/opentelemetry/README.md Co-authored-by: Dave Henderson * Update link in README.md Co-authored-by: Dave Henderson * Update documentation in README.md Co-authored-by: Dave Henderson * Update link to naming spec in README.md Co-authored-by: Dave Henderson * Rename module from opentelemetry to tracing Co-authored-by: Dave Henderson * Rename span_name to span Co-authored-by: Dave Henderson * Rename span_name to span Co-authored-by: Dave Henderson * Simplify otel resource creation Co-authored-by: Dave Henderson * handle extra attributes Co-authored-by: Dave Henderson * update go.opentelemetry.io/otel/semconv to 1.7.0 Co-authored-by: Dave Henderson * update go.opentelemetry.io/otel version * remove environment variable handling * always use tracecontext,baggage as propagators * extract tracer name into variable * rename OpenTelemetry to Tracing * simplify resource creation * update go.mod * rename package from opentelemetry to tracing * cleanup tests * update Caddyfile example in README.md * update README.md * fix test * fix module name in README.md * fix module name in README.md * change names in README.md and tests * order imports * remove redundant tests * Update documentation README.md Co-authored-by: Dave Henderson * Fix grammar Co-authored-by: Dave Henderson * Update comments Co-authored-by: Dave Henderson * Update comments Co-authored-by: Dave Henderson * update go.sum * update go.sum * Add otelhttp instrumentation, update OpenTelemetry libraries. * Use otelhttp instrumentation for instrumenting HTTP requests. This change uses context.WithValue to inject the next handler into the request context via a "nextCall" carrier struct, and pass it on to a standard Go HTTP handler returned by otelhttp.NewHandler. The underlying handler will extract the next handler from the context, call it and pass the returned error to the carrier struct. * use zap.Error() for the error log * remove README.md * update dependencies * clean up the code * change comment * move serveHTTP method from separate file * add syntax to the UnmarshalCaddyfile comment * go import the file * admin: Write proper status on invalid requests (#4569) (fix #4561) * update dependencies Co-authored-by: Dave Henderson Co-authored-by: Francis Lavoie Co-authored-by: Vibhav Pant Co-authored-by: Alok Naushad Co-authored-by: Cedric Ziel --- modules/caddyhttp/tracing/tracer.go | 108 ++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 modules/caddyhttp/tracing/tracer.go (limited to 'modules/caddyhttp/tracing/tracer.go') diff --git a/modules/caddyhttp/tracing/tracer.go b/modules/caddyhttp/tracing/tracer.go new file mode 100644 index 0000000..ce23944 --- /dev/null +++ b/modules/caddyhttp/tracing/tracer.go @@ -0,0 +1,108 @@ +package tracing + +import ( + "context" + "fmt" + "net/http" + + "github.com/caddyserver/caddy/v2" + + caddycmd "github.com/caddyserver/caddy/v2/cmd" + "github.com/caddyserver/caddy/v2/modules/caddyhttp" + "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp" + "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc" + "go.opentelemetry.io/otel/propagation" + "go.opentelemetry.io/otel/sdk/resource" + sdktrace "go.opentelemetry.io/otel/sdk/trace" + semconv "go.opentelemetry.io/otel/semconv/v1.7.0" + "go.uber.org/zap" +) + +const ( + webEngineName = "Caddy" + defaultSpanName = "handler" + nextCallCtxKey caddy.CtxKey = "nextCall" +) + +// nextCall store the next handler, and the error value return on calling it (if any) +type nextCall struct { + next caddyhttp.Handler + err error +} + +// openTelemetryWrapper is responsible for the tracing injection, extraction and propagation. +type openTelemetryWrapper struct { + propagators propagation.TextMapPropagator + + handler http.Handler + + spanName string +} + +// newOpenTelemetryWrapper is responsible for the openTelemetryWrapper initialization using provided configuration. +func newOpenTelemetryWrapper( + ctx context.Context, + spanName string, +) (openTelemetryWrapper, error) { + if spanName == "" { + spanName = defaultSpanName + } + + ot := openTelemetryWrapper{ + spanName: spanName, + } + + res, err := ot.newResource(webEngineName, caddycmd.CaddyVersion()) + if err != nil { + return ot, fmt.Errorf("creating resource error: %w", err) + } + + traceExporter, err := otlptracegrpc.New(ctx) + if err != nil { + return ot, fmt.Errorf("creating trace exporter error: %w", err) + } + + ot.propagators = propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}) + + tracerProvider := globalTracerProvider.getTracerProvider( + sdktrace.WithBatcher(traceExporter), + sdktrace.WithResource(res), + ) + + ot.handler = otelhttp.NewHandler(http.HandlerFunc(ot.serveHTTP), ot.spanName, otelhttp.WithTracerProvider(tracerProvider), otelhttp.WithPropagators(ot.propagators)) + return ot, nil +} + +// serveHTTP injects a tracing context and call the next handler. +func (ot *openTelemetryWrapper) serveHTTP(w http.ResponseWriter, r *http.Request) { + ot.propagators.Inject(r.Context(), propagation.HeaderCarrier(r.Header)) + next := r.Context().Value(nextCallCtxKey).(*nextCall) + next.err = next.next.ServeHTTP(w, r) +} + +// ServeHTTP propagates call to the by wrapped by `otelhttp` next handler. +func (ot *openTelemetryWrapper) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error { + n := &nextCall{ + next: next, + err: nil, + } + ot.handler.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), nextCallCtxKey, n))) + + return n.err +} + +// cleanup flush all remaining data and shutdown a tracerProvider +func (ot *openTelemetryWrapper) cleanup(logger *zap.Logger) error { + return globalTracerProvider.cleanupTracerProvider(logger) +} + +// newResource creates a resource that describe current handler instance and merge it with a default attributes value. +func (ot *openTelemetryWrapper) newResource( + webEngineName, + webEngineVersion string, +) (*resource.Resource, error) { + return resource.Merge(resource.Default(), resource.NewSchemaless( + semconv.WebEngineNameKey.String(webEngineName), + semconv.WebEngineVersionKey.String(webEngineVersion), + )) +} -- cgit v1.2.3